Hi, can someone enlighten me as to the difference between a PRI and a "Digital Trunk" (other than cost)? I do understand PRI (B-channel signaling, incoming/outgoing call setup, D channel for voice/data, etc), but I'm not quite sure how that compares with what my vendor is calling a "Digital Trunk" (specifically in contrast to a PRI). The PRI is about twice the cost. If this is just a channelized T1 (24 64k voice/data "channels'), would they each be assigned a specific phone number, or is there further flexibility in sending/receiving calls, callerid (receive or send), etc? Feeling ignorant here.... Thanks!
> Hi, can someone enlighten me as to the difference between a PRI and a > "Digital Trunk" (other than cost)?Barry, A "digital trunk" from the telco is most likely as you said - 24 channels of 64k voice. (I know, technically it's "data" but the "data" is just digitized voice.) Think of the digital trunk as the equivalent of 24 analog phone lines. They can all be in hunt, some in hunt or none. (Depends on the carrier and your specific needs.) They can be inbound, outbound or both. (Again, depends on your needs.) On the digital trunk, the signaling is all done on the individual channels - if a call comes in on channel 7 then channel 7 will see a signal from the telco - frequently this is a "wink" signal. A PRI is, again as you said, 23 voice channel with one data/signaling channels, unless you're outside the USA in which case it's 30 and two. All of the call setup, tear down, etc. info is sent on the D channel(s). Since the D channel is actual data, and not just touch tones and hook flashes, the PRI can actually do more. For example, you can customize the caller ID info that is sent out, whereas on your digital trunk the carrier will control what caller ID is sent to the called party. If you want some more detailed info on ISDN (both PRI and BRI) then check this out: http://www.ralphb.net/ISDN/intro.html I'm surprised that your carrier is charging more for a PRI. Here in California my carriers are dying to sell me PRI's instead of digital trunks because they feel PRI's are easier to maintain. (I don't know if that's true, but I've had more than one carrier tell me that.) Who is your carrier and where are you located? -MC
I don't know about what our LEC is calling a "digital trunk" but verizon tried to offer me something like this for a location that they couldn't offer a PRI, basically it was a just a voice T1 (24 channels), didn't have features like Caller ID, setting outbound caller ID, ANI, etc. YMMV. On 7/25/06, Barry D. Hassler <Barry.Hassler@hcst.com> wrote:> > Hi, can someone enlighten me as to the difference between a PRI and a > "Digital Trunk" (other than cost)? > > I do understand PRI (B-channel signaling, incoming/outgoing call setup, > D channel for voice/data, etc), but I'm not quite sure how that compares > with what my vendor is calling a "Digital Trunk" (specifically in > contrast to a PRI). The PRI is about twice the cost. > > If this is just a channelized T1 (24 64k voice/data "channels'), would > they each be assigned a specific phone number, or is there further > flexibility in sending/receiving calls, callerid (receive or send), etc? > > Feeling ignorant here.... > > Thanks! > _______________________________________________ > --Bandwidth and Colocation provided by Easynews.com -- > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20060725/7de14b0a/attachment.htm
Cheaper depends on the age of the switch at the CO you are connecting to. In some parts of Tenn.. I cannot get a PRI but a T1 will be just fine, alas NO CID, or enhanced features but a T1 nonetheless. I my old CO PRIs had to be FXed (Brought in from another CO) My CO was a 1A and but not have the SW and/or ability to provide ISDN services as the other 5E did. This was a problem as the contract stated that once ISDN services were available in my CO we would have to change over to that exchange. We later moved into the area served by the 5E and the change did not have to happen. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20060725/60f6e444/attachment.htm
Thanks for the answers folks. I think I now understand that indeed, the "Digital Trunk" is really nothing more than the same analog services, just delivered digitally. no outbound ANI (of especial interest), etc.... This is in the Dayton Ohio area, major telco vendor. I'll have to pursue the differences with them further, as the pricing is about double for the PRI vs the "Digital Trunk". I'd like to move 7 analog lines to a digital interface, but just can't cost-justify it in this scenario :-( On Tue, 2006-07-25 at 15:25 -0400, Barry D. Hassler wrote:> Hi, can someone enlighten me as to the difference between a PRI and a > "Digital Trunk" (other than cost)? > > I do understand PRI (B-channel signaling, incoming/outgoing call setup, > D channel for voice/data, etc), but I'm not quite sure how that compares > with what my vendor is calling a "Digital Trunk" (specifically in > contrast to a PRI). The PRI is about twice the cost. > > If this is just a channelized T1 (24 64k voice/data "channels'), would > they each be assigned a specific phone number, or is there further > flexibility in sending/receiving calls, callerid (receive or send), etc? > > Feeling ignorant here.... > > Thanks! > _______________________________________________ > --Bandwidth and Colocation provided by Easynews.com -- > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users________________________________________________________________________ Barry D. Hassler President HCST 2332 Grange Hall Road Beavercreek, Ohio 45431-2345 http://www.hcst.net/ barry.hassler@hcst.com +1 937-427-9000 +1 937-427-8706 FAX FWD: 3934279000 (655480) HCST*Net Support Issues: please email support@hcst.net Billing Issues: Please email billing@hcst.net -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20060725/d1a49f22/attachment.htm